For many years there has been acute awareness of the need to provide safety on common carriers for physically challenged who are restricted to traveling in a wheelchair or other personal vehicle. Numerous efforts have been made to provide tie down and anchoring devices for securing a wheelchair in position in a bus or other carrier. Awareness of this need has led to the enactment of safety laws which require a vehicle to be equipped with spaces for parking wheelchairs or other personal devices for securement safely to the vehicle. The challenge has been for designers to provide a tie down device which is secure, fail safe and at the same time easy and convenient to operate by the occupant or vehicle driver. Numerous different devices have been proposed in effort to solve these problems as evidence in U.S. Pat. Nos. 4,973,022 and 5,344,265.
Many of these devices suffer the shortcoming that they are impossible for the wheelchair occupant to operate unassisted and, even with help may take several minutes to secure in place. See U.S. Pat. No. 4,973,022.
Examples of wheelchair tie down devices include a three point anchoring system including an anchor for attachment to the rear of the wheelchair and personnel securing belt as well as a front wheelchair attachment assembly as shown in U.S. Pat. No. 6,113,325.
Other efforts have led to proposal that a wheelchair tie down device include a locking mechanism mounted to the vehicle floor and a bar mounted to the underside of the wheelchair. The locking mechanism includes a stationary locking structure with a pivoting lock arm and a slot configured to receive the bar. See U.S. Pat. No. 5,628,595.
An upstanding securing stanchion has been proposed for mounting to the floor of a transport vehicle to engage and couple with a wheelchair as shown in U.S. Pat. No. 5,567,095.
In has been proposed to provide a pair of clamp posts having jaw members positioned to engage the wheelchair under frame. A device of this type is described in U.S. Pat. No. 4,973,022.
Other clamping devices have been proposed for attachment to the floor of the transport vehicle and include a pivotable clamped to an adapter intended to be mounted on the underside of the wheelchair. This type is shown in U.S. Pat. No. 4,805,954.
Other efforts have led to a proposal that an electromechanical system including an automated tie down having a latching device mounted to the floor of the transport vehicle, a tie down bracket bolted on the wheelchair and adjustable chokes to secure the wheelchair in place. A device of this type is shown in U.S. Pat. No. 4,730,964.
Devices have been proposed which include a transverse back stop mounted to the floor of the transport vehicle, vertical plates extending longitudinally from the base of the wheelchair and a transverse bail having a cross rod rotatably extended to engage notches in the four ends of the plates. A device of this type is described in U.S. Pat. No. 4,623,289.
It has also been proposed to provide a pair of stands having wheel guide arms for receiving a portion of the hand wheels of a wheelchair, along with latches for securing the wheels in position. A device of this type is shown in U.S. Pat. No. 4,062,209.
I previously worked on a tie down mechanism including tie down straps for engaging the frame of the wheelchair and a take up mechanism for taking up slack in the straps. I assigned my rights in U.S. Pat. No. 5,888,038 on this device to American Seating Company. While this device was built to fill certain needs, it has been recognized that some challenge is presented to the bus operator to locate and retrieve the attachment mechanisms and secure the wheelchair in place. In effort to overcome this shortcoming, a device was proposed which includes a seat belt housing and restraining device mountable to the transit vehicle for retraction of a restraining element and a cable for controlling retraction of such restraining element to operated by a control remote from the housing such for the convenient of the vehicle operator. A device of this type is shown in U.S. Pat. No. 6,524,039.
Other efforts have led to the proposal that wheelchairs incorporate a universal adapter for coupling with a docking assembly latch mounted in a transit vehicle. A device of this type is shown in U.S. Pat. No. 6,474,916. These devices require modification of conventional wheelchairs.
The foregoing devices fail to address the preference by wheelchair occupants that they have some degree of independence in themselves securing the wheelchair in its constrained condition on the transit vehicle.